There exist several industrial standards in the fields of video display system. Each video display standard has it own display timing which is different from those of other standards. Among others, the NTSC, PAL display mode of TV system and the VGA progressive display mode of Personal Computer system are well known and commonly employed in the industry.
The following table is the summary of the scan parameters of the mentioned video display standards.
______________________________________ NTSC PAL VGA ______________________________________ Horizontal 15734 Hz 15625 Hz 31.5 KHz frequency vertical 59.94 Hz 50 Hz 60 Hz frequency scan line 525 625 / resolution / / 640*480 scan mode interlace interlace progressive ______________________________________
In the field of multi-media application, the operation of output and display of the digital images require scan timing signals, which follow multiple industrial standards, and, accordingly, the multi-media information may be displayed as required in accordance with the standard selected.
In order to display the information in accordance with multiple widely used industrial standards, the instant invention provides a timing generator which is capable of outputing scan timing of various industrial standards.
The purpose and utilization of the horizontal, vertical and composite timing signals, etc. mentioned hereinafter are all well known in this field and further elaboration is deem unnecessary for persons skilled in the arts.